Cairo: Thousands of police were deployed on Monday across Cairo in anticipation of demonstrations to protest the government’s decision to cede control of two strategic Red Sea islands to Saudi Arabia.

Riot police backed by armoured vehicles took up positions at Cairo’s Tahrir square, the epicentre of Egypt’s 2011 uprising, as well as on the city’s ring road, downtown and at a suburban square where security forces broke up violent protests by Muslim Brotherhood supporters on August 14, 2013.

Monday’s planned demonstrations would be the second wave of protests this month against the decision to give up control of the islands at the mouth of the Gulf of Aqaba. On April 15, about 2,000 demonstrators protested in downtown Cairo over the islands.

That protest was the largest against the government since President Abdul Fattah Al Sissi assumed office in 2014.

Chants of “leave,” and “the people want to bring down the regime” rang out in the downtown area on that day, harkening back to the 2011 uprising that forced autocrat Hosni Mubarak to step down after nearly 30 years in power.

Authorities have made dozens of arrests in recent days, with the arrests continuing until just hours before the planned demonstrations. Freedom for the Brave, an activist group, says nearly 100 people have been arrested since the latest round of detentions began last week.

Egypt says the islands of Tiran and Sanafir, off the southern coast of the Sinai Peninsula, belong to Saudi Arabia, which placed them under Cairo’s protection in 1950 because it feared Israel might attack them. The government says officials and experts have for years negotiated with their Saudi counterparts the demarcation of the two countries’ sea borders and at the end agreed that the islands are inside Saudi Arabia’s territorial waters.

The announcement came during a visit to Egypt earlier this month by King Salman Bin Abdul Aziz, during which the kingdom announced a multi-billion-dollar package of aid and investment to Egypt, fuelling charges that the islands were sold off.

President Al Sissi insists that Egypt has not surrendered an “inch” of its territory and in a recent televised address he demanded that people stop talking about the issue.

April 25 is a national holiday in Egypt marking the completion of Israel’s pullout from Sinai, which it occupied in the 1967 Middle East war.

The Interior Ministry said the deployment of police is designed to protect “peaceful” citizens who wish to celebrate.

The planned demonstrations have come at a time when Al Sissi is facing criticism over the ailing economy, an insurgency by Islamist militants in Sinai and the fallout from the abduction, torture and killing of an Italian doctoral student in Cairo. The incident has poisoned relations with Italy, one of Al Sissi’s staunchest supporters in the European Union and Egypt’s biggest European trade partner.

Al Sissi says Egypt’s security forces had nothing to do with the killing, blaming “evil forces” for attempting to isolate Egypt internationally.